Huntington's Disease

What Is It?

Huntington's disease, also sometimes referred to as Huntingtons Chorea (pronounce similar to Korea), is a autosomal dominant genetic disorder which affects the nervous system, the brain in particular. It is caused by a genetic mutation on chromosome 4. Because this Huntington gene is a dominant gene, you only need one copy of the bad gene to develop the disorder. In other words, if one parent has the disease, their offspring have a 50% chance of getting that gene and the disease.

The actually mutation in Huntington's disease is an excessive amount of repeating portions of DNA, what is known as a CAG repeat. The more repeats a person has in their gene, the more likely they will develop symptoms at a younger age. As it is passed down in a family, these repeats tend to increase. In other words, as time goes on, the disease tends to present at an earlier and earlier age.

Generally, the disease presents somewhere in the 30's to 40's although there are rare specific examples of early-onset forms which present earlier.

What Types of Symptoms Are Typical?

The exact time of onset and types of first symptoms in Huntington's disease can be variable, but many patients present first with behavioral changes that predate the movement problems for which the disease is most well known. These can include various changes in behavior, hallucinations, irritability, paranoia or even psychosis.

However, the hallmark symptoms of Huntington's disease are those that affect movement. Patients develop abnormal movements which can involve multiple body parts. These can range from things like facial grimacing and head turning to the classic quick and purposeless wild movements of the extremities and other body parts. These movements are known as choreiform movements which comes from the same root word as choreograph. They were called this because they are sometimes described as "dancelike" and explains why the disease is sometimes referred to as Huntingtons Chorea. These movement problems can affect gait and other motor functioning.

This is a progressive disease, meaning that after it presents, it slowly progresses with further symptoms and more severe symptoms. Later in the course of the disease the patients intellect and cognitive ability can be affected. This dementia can cause confusion, problems with judgement and memory, language and speech problems and personality changes.

Unfortunately, Huntington's disease is a continuously progressive disorder that will lead to more and more severe disability over time. After initial diagnosis, most patients die due to the disease within approximately 15 to 20 years.

It should be noted that because of the profound impact this debilitating and lethal chronic disease has on patients, depression is very common in these individuals. Suicide is not uncommon. Many patients may benefit from counseling, support groups or a psychologist or psychiatrist.

How Is The Diagnosis Typically Made?

As with many diseases, often the first testing done if Huntingtons disease is suspected is a thorough history and physical examination by a qualified physician. Although a general practitioner may do the initial work up, a referral to a neurologist who specializes in diseases of the nervous system is often warranted. On examination, evidence of dementia, abnormal movements and reflexes and others may be obvious and help support the diagnosis.

Scanning of the brain, such as CT and MRI, may also be done. These tests are primarily to rule out other pathologies which may present in a similar manner and may be confused for Huntington's disease. However, those with moderate to advanced disease do have subtle changes in the brain with this disease which may be seen, including loss of brain tissue in some specific locations in the brain.

Ultimately, the final diagnosis of this genetic disease usually relies on genetic testing. Blood can be sent for genetic tests that can identify the presence of the Huntington gene.

What Are Some Common Treatments?

Unfortunately, there is no known cure for Huntington's disease and no treatment has a profound effect on the progression of the disease. There are medications which are used with the goal of slowing down the progression of the disease and limiting some of the symptoms of the disease, but in general they do not profoundly affect the natural course of the disease and do not prolong life expectancy. For example, some of the abnormal movements may respond in some patients to drugs such as dopamine blockers, amantadine and others.

As mentioned above, depression and suicide are common in patients diagnosed with Huntington's disease. Therefore, mental health care and treatment may be important. Trying to improve the mood and quality of life of these patients may be some of the best things that can be done for them, even if the primary disease cannot be treated.

Eventually, patients with Huntington's disease will progress to the level that they will not be able to care for themselves and will need round-the-clock care, often from a skilled nursing facility or home nurse. Again, although the disease cannot be cured, making the patient as comfortable as possible, both mentally and physically, are often important goals of their care.

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Important Note: This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.

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